FLARM Hub 1.20 to 1.22. This will be fixed in a later version.
In the "IGC Task Editor, longitude values between 08000000 (W or E) and 10000000 are incorrectly flagged as invalid.
- Add your waypoint with a Longitude value of "00000000W"
- Move the waypoint to the top by drag and dropping it
- Edit the waypoint by clicking on the "Pen" button, change the "Longitude" field to the desired value and end editing by clicking again on the "Pen" button
- Move back the waypoint to the desired position by drag and dropping it again